Display device and method of manufacturing the same

Abstract

A display device includes a thin-film transistor, an interlayer insulating layer on the thin-film transistor, a source electrode, a drain electrode, and an auxiliary electrode on the interlayer insulating layer, each of the source electrode, the drain electrode, and the auxiliary electrode including a main conductive layer and a sub conductive layer on the main conductive layer, and a via insulating layer on the source electrode, the drain electrode and the auxiliary electrode, the via insulating layer covering the source electrode and the drain electrode and exposing a portion of an upper surface of the second conductive layer of the auxiliary electrode. The via insulating layer includes a first part spaced apart from the upper surface of the second conductive layer of the auxiliary electrode, and the second part adjacent to side surfaces of the main conductive layer and the sub conductive layer of the auxiliary electrode.

What is claimed is: 
     
         1 . A display device comprising:
 a thin-film transistor disposed on a substrate;   an interlayer insulating layer disposed on the thin-film transistor;   a source electrode, a drain electrode and an auxiliary electrode disposed on the interlayer insulating layer and spaced apart from each other, each of the source electrode, the drain electrode, and the auxiliary electrode including:
 a main conductive layer, and 
 a sub conductive layer disposed on an upper surface of the main conductive layer; and 
   a via insulating layer disposed on the source electrode, the drain electrode, and the auxiliary electrode, the via insulating layer covering the source electrode and the drain electrode and exposing a portion of an upper surface of the sub conductive layer of the auxiliary electrode, wherein   the via insulating layer includes:
 a first part spaced apart from the upper surface of the sub conductive layer of the auxiliary electrode in a thickness direction, and 
 a second part disposed on the first part and adjacent to side surfaces of the main conductive layer of the auxiliary electrode and side surfaces of the sub conductive layer of the auxiliary electrode, and 
   side surfaces of the first part are inwardly protruded from side surfaces of the second part to form an undercut shape of the via insulating layer.   
     
     
         2 . The display device of  claim 1 , wherein
 each of the source electrode and the drain electrode further includes an upper conductive layer, the upper conductive layer disposed on the upper surface of the sub conductive layer of each of the source electrode and the drain electrode, and   the upper conductive layer of each of the source electrode and the drain electrode is in contact with the via insulating layer.   
     
     
         3 . The display device of  claim 2 , wherein
 a distance between a lower surface of the first part of the via insulating layer and the upper surface of the sub conductive layer of the auxiliary electrode is substantially same as a thickness of the upper conductive layer of each of the source electrode and the drain electrode.   
     
     
         4 . The display device of  claim 3 , wherein
 the main conductive layer of each of the source electrode, the drain electrode, and the auxiliary electrode includes at least one of copper (Cu) and aluminum (Al),   the sub conductive layer of each of the source electrode, the drain electrode, and the auxiliary electrode includes at least one of titanium (Ti), molybdenum (Mo), and a conductive oxide, and   the upper conductive layer of each of the source electrode and the drain electrode includes at least one of Cu and Al.   
     
     
         5 . The display device of  claim 1 , further comprising:
 a pixel electrode disposed on the via insulating layer and connected to the drain electrode through a contact hole penetrating the via insulating layer,   wherein the pixel electrode does not overlap the auxiliary electrode.   
     
     
         6 . The display device of  claim 5 , further comprising:
 a pixel-defining film disposed on the pixel electrode and the via insulating layer to expose a portion of an upper surface of the pixel electrode and a portion of the upper surface of the sub conductive layer of the auxiliary electrode; and   a light-emitting layer disposed on the pixel-defining film,   wherein the light-emitting layer is in contact with the portion of the upper surface of the pixel electrode exposed by the pixel-defining film and is disconnected in the portion of the auxiliary electrode exposed by the pixel-defining film.   
     
     
         7 . The display device of  claim 6 , further comprising:
 a common electrode disposed on the light-emitting layer,   wherein the common electrode surrounds the first part of the via insulating layer and is in contact with a portion of the upper surface of the sub conductive layer of the auxiliary electrode.   
     
     
         8 . The display device of  claim 7 , further comprising:
 a light-emitting dummy layer disposed on the upper surface of the sub conductive layer of the auxiliary electrode, the light-emitting dummy layer and the light-emitting layer formed of a same layer,   wherein the light-emitting dummy layer is disconnected from the light-emitting layer.   
     
     
         9 . The display device of  claim 8 , further comprising:
 a dummy common electrode disposed on the upper surface of the sub conductive layer of the auxiliary electrode and covering the light-emitting dummy layer, the dummy common electrode and the common electrode formed of a same layer,   wherein the dummy common electrode is spaced apart from the common electrode, and is disposed on the upper surface of the sub conductive layer of the auxiliary electrode.   
     
     
         10 . The display device of  claim 8 , wherein the common electrode covers the light-emitting dummy layer and a portion of the upper surface of the sub conductive layer of the auxiliary electrode that is exposed by the light-emitting dummy layer. 
     
     
         11 . A display device comprising:
 a thin-film transistor disposed on a substrate;   an interlayer insulating layer disposed on the thin-film transistor;   a source electrode, a drain electrode, and an auxiliary electrode disposed on the interlayer insulating layer and spaced apart from each other, each of the source electrode, the drain electrode, and the auxiliary electrode including:
 a main conductive layer, and 
 a sub conductive layer disposed on an upper surface of the main conductive layer; and 
   a via insulating layer disposed on the source electrode, the drain electrode, and the auxiliary electrode, the via insulating layer covering the source electrode and the drain electrode and including an opening exposing an upper surface of the sub conductive layer of the auxiliary electrode, wherein   the opening of the via insulating layer includes:
 a first opening part exposing a first portion of the upper surface of the sub conductive layer of the auxiliary electrode, and 
 a second opening part overlapping the first opening part, having a width greater than a width of the first opening part, and exposing a second portion of the upper surface of the sub conductive layer of the auxiliary electrode greater than the first portion of the upper surface of the sub conductive layer of the auxiliary electrode. 
   
     
     
         12 . The display device of  claim 11 , wherein
 each of the source electrode and the drain electrode further includes an upper conductive layer, the upper conductive layer disposed on the upper surface of the sub conductive layer of each of the source electrode and the drain electrode, and   the upper conductive layer of each of the source electrode and the drain electrode is in contact with the via insulating layer.   
     
     
         13 . The display device of  claim 12 , wherein
 the first opening part of the opening of the via insulating layer is spaced apart from the upper surface of the sub conductive layer of the auxiliary electrode in a thickness direction, and   a distance between a lower portion of the first opening part of the opening of the via insulating layer and the upper surface of the sub conductive layer of the auxiliary electrode is substantially same as a thickness of the upper conductive layer of each of the source electrode and the drain electrode.   
     
     
         14 . The display device of  claim 13 , wherein
 the main conductive layer of each of the source electrode, the drain electrode, and the auxiliary electrode includes at least one of copper (Cu) and aluminum (Al),   the sub conductive layer of each of the source electrode, the drain electrode, and the auxiliary electrode includes at least one of titanium (Ti), molybdenum (Mo), and a conductive oxide, and   the upper conductive layer of each of the source electrode and the drain electrode includes at least one of Cu and Al.   
     
     
         15 . The display device of  claim 11 , further comprising:
 a pixel electrode disposed on the via insulating layer and connected to the drain electrode through a contact hole penetrating the via insulating layer,   wherein the pixel electrode does not overlap the auxiliary electrode.   
     
     
         16 . The display device of  claim 15 , further comprising:
 a pixel-defining film including:
 a first opening exposing a portion of an upper surface of the pixel electrode, and 
 a second opening exposing a portion of the upper surface of the sub conductive layer of the auxiliary electrode; and 
   a light-emitting layer disposed on the pixel-defining film,   wherein the light-emitting layer is in contact with the upper surface of the pixel electrode in the first opening of the pixel-defining film, and is disconnected in the second opening of the pixel-defining film.   
     
     
         17 . The display device of  claim 16 , further comprising:
 a common electrode disposed on the light-emitting layer,   wherein the common electrode extends to the opening of the via insulating layer beyond the second opening of the pixel-defining film and is in contact with a portion of the upper surface of the sub conductive layer of the auxiliary electrode.   
     
     
         18 . The display device of  claim 17 , further comprising:
 a light-emitting dummy layer disposed on the upper surface of the sub conductive layer of the auxiliary electrode, the light-emitting dummy layer and the light-emitting layer formed of a same layer,   wherein the light-emitting dummy layer is disconnected from the light-emitting layer.   
     
     
         19 . A method of manufacturing a display device, comprising:
 forming a thin-film transistor on a substrate;   forming an interlayer insulating layer on the thin-film transistor;   forming a source electrode, a drain electrode, and an auxiliary electrode as a same layer on the interlayer insulating layer, each of the source electrode, the drain electrode, and the auxiliary electrode including:
 a main conductive layer, 
 a sub conductive layer disposed on an upper surface of the main conductive layer, and 
 an upper conductive layer disposed on an upper surface of the sub conductive layer; 
   forming a via insulating layer on the source electrode, the drain electrode, and the auxiliary electrode, the via insulating layer covering the source electrode, the drain electrode and exposing the upper surface of the sub conductive layer of the auxiliary electrode;   forming a pixel electrode layer on the via insulating layer;   forming a photoresist pattern on a portion of the pixel electrode layer overlapping the source electrode and the drain electrode; and   forming an undercut in the via insulating layer by etching the upper conductive layer of the auxiliary electrode and a portion of the pixel electrode layer where the photoresist pattern is not formed.   
     
     
         20 . The method of  claim 19 , wherein
 the main conductive layer and the upper conductive layer of each of the source electrode, the drain electrode and the auxiliary electrode include at least one of copper (Cu) and aluminum (Al), and   the sub conductive layer of each of the source electrode, the drain electrode, and the auxiliary electrode includes at least one of titanium (Ti), molybdenum (Mo), and a conductive oxide.